Sherlock Holmes was beset by ennui, his trusty sidekick, Dr. John Watson, being otherwise engaged with his wife at their humble abode. The lack of clients and the absence of any intriguing cases presented by his brother, Mycroft, had left him in a state of listlessness. His remarkable faculties, so accustomed to being stimulated by the intricacies of crime and detection, were beginning to languish from disuse.

However, his ears perked up as he detected the sound of footsteps ascending the stairs, and he straightened up with anticipation. 'A new challenge, perhaps?' he mused, as he awaited the arrival of the individual, whose lightweight tread and confident gait betrayed a sense of purpose. The footsteps grew louder, and Sherlock's eyes narrowed as he focused his attention on the approaching stranger.

Upon reaching the door, the man knocked, and Sherlock, still reclining on the couch, responded with a languid,

— “The door is open, pray, let yourself in.”

His eyes never left the door, his gaze piercing and inquiring, as he awaited the entrance of the unknown visitor, whose every step and movement was being meticulously scrutinized by the great detective's observant mind.